1. Field of the Invention
The present invention relates to a ball screw device, and more particularly to a ball screw device having a circulating device for effectively and smoothly receiving and guiding the balls or the rollers or the bearing members to move relative to the ball nut and the screw shaft, and for facilitating the rotational movement of the ball nut and the screw shaft relative to each other in great rotational speeds.
2. Description of the Prior Art
Typical ball screw devices comprise a ball nut rotatably and/or moveably engaged onto a screw shaft, and normally arranged to allow the ball nut to be rotated and/or moved relative to the screw shaft in great rotational speeds. For allowing the ball nut to be smoothly rotated and moved relative to the screw shaft, a suitable bearing device or lubricating structure is further required to be provided and engaged between the ball nut and the screw shaft, for facilitating the rotational movement between the ball nut and the screw shaft.
For example, U.S. Pat. No. 3,971,2648 to Detraz et al. discloses one of the typical screw-and-nut mechanism with ball or roller recirculation including a ball recirculation channel comprising bent, tubular inlet and outlet elements connected to each other by a connecting means, the tubular elements being engaged in a bore of the nut member in such a way as to emerge at the bottom of the thread.
However, the tubular elements are required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the tubular elements may be distorted such that the balls or the rollers or the bearing members may not suitably move through the tubular elements.
U.S. Pat. No. 4,953,419 to Schlenker, and U.S. Pat. No. 5,063,809 to Schlenker disclose two further typical ball screw and nut assemblies each including a ball return tube having one or more bent portions or elbows for guiding the balls or the rollers or the bearing members.
However, similarly, the return tubes are also required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the return tubes may be distorted such that the balls or the rollers or the bearing members may not suitably move through the return tubes.
U.S. Pat. No. 5,014,568 to Schlenker discloses a still further typical ball screw and nut assembly including a deflector having a curved and elongate body, and a threaded stem rigidly affixed to the body and secured to or integral with the body, and one or more transfer tubes for guiding the balls or the rollers or the bearing members.
However, similarly, the transfer tubes are also required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the transfer tubes may be distorted such that the balls or the rollers or the bearing members may not suitably move through the transfer tubes.
U.S. Pat. No. 6,023,991 to Tabe et al. discloses a still further typical ball screw device also including one or more circulation tubes attached to the ball nut for guiding the balls or the rollers or the bearing members.
However, similarly, the circulation tubes are also required to be bent from a longitudinal tubular member, and the corner areas or the bent portions of the circulation tubes may be distorted such that the balls or the rollers or the bearing members may not suitably move through the circulation tubes.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ball screw devices for such as machine tools or the like.